Velocity profiles were measured up to a minimum distance of 0.15 μm from the wall for tube flow of aqueous solutions of anionic Polyacrylamides (Praestol from the Stockhausen Corporation, at a concentrationc0=0.25percentage by weight). The profiles measured could be recalculated on the basis of the flow curve. Extrapolation of the profile to the wall resulted in finite velocity values (slip‐velocityvs). This slip phenomenon could not be calculated in advance on the basis of the flow curve alone. Within the range of wall shear stressτwexamined, the dependence ofvxonτwwas linear for a given polymer concentration and exhibited no threshold. The slip velocityvsdecreased if capillary active substances or strong electrolytes were added to the solution; divalent cations(Ca+ +) being ten times more effective than mono‐valent ones(Na+).The increment of flow velocity fromv=0tov=vswith increasing distance from the wall occurs within a fluid layer which borders the wall (or a layer of adsorbed macromolecules resp.) and which possesses a width smaller thanδ=0.15 μm(i.e. the axial resolution of the microanemometer). When assuming a value of δ between 0.022 μm and 0.1 μm, the viscosityηsof the fluid within the slip interval is calculated to be 1 cP up to 4.57 cP, respectively. The value ofηsis shear independent and at least seven times smaller than the viscosity measured by means of the viscosimeter. The results indicate that the Polyacrylamide solution does not glide directly along the wall but, instead, by mediation of a low viscous Newtonian fluid lining the wall.